The purpose of this proposal is to test the efficacy of a behavioral intervention for depression in nursing homes. The program, BE-ACTIV, has been adapted and piloted in nursing homes, and shows promise of reducing depression in residents with major and minor depression. The intervention is conceptually based on Lewinsohn's behavioral theory of depression and derived from Teri's effective, outpatient intervention for elders with dementia. It involves collaboration between a mental health therapist and nursing home Activities Department staff, and is tailored to the individual resident. The goal is to increase opportunities for pleasant events, thus increasing activity and positive affect. There are 2 specific aims: (1) using a randomized, controlled, two-group design, to compare outcomes for depressed residents receiving the BE-ACTIV program with those receiving treatment as usual in their nursing homes;and (2) to evaluate the treatment mechanisms, including staff attention, increased activity levels, and increased positive affect, related to improvement following participation in BE-ACTIV. The latter aim employs both within-subject process measures and between-subject comparisons. Measures include diagnostic evaluation, depression and mood rating scales, general functioning, observed affect and activity participation, behavior problems, resident satisfaction, and staff burden. Analyses will make use of random effects modeling to analyze within- and between-subject variability in intervention process and treatment response. Public Health Relevance: Nursing home residents are at a significantly higher risk for depression than community-residing elders;up to 50% of nursing home residents are affected by significant depressive symptoms. The health and cognitive multiple comorbidity of this population makes treatment, and treatment research, extremely challenging. Although we have a good understanding of the epidemiology and manifestations of depression in late life and are beginning to apply effective treatments to some groups of elders, the benefits of the past decade of research have yet to reach these frailest elders.